12 Advanced measuring functions
85
12.5
Upper limit of the flow velocity
Single outliers caused by heavily disturbed surroundings can appear among the measured values of the flow velocity. If
these outliers are not ignored, they will affect all derived physical quantities, which will then be unsuitable for the integra-
tion (e.g., pulse outputs).
It is possible to ignore all measured flow velocities exceeding the preset upper limit. These measured values will be
marked as outliers.
The upper limit of the flow velocity is set in
Special Funct.
\
SYSTEM settings
\
Measuring
\
Velocity limit
.
If the flow velocity is higher than the upper limit,
• the flow velocity will be marked as invalid. The physical quantity cannot be determined.
• an exclamation point (!) will be displayed after the unit of measurement. In case of a normal error, an interrogation point
(
?
).
12.6
Cut-off flow
The cut-off flow is a lower limit for the flow velocity. All measured flow velocities that are lower than the limit and their de-
rived values are set to zero.
The cut-off flow can depend on the flow direction. The cut-off flow is set in
Special Funct.
\
SYSTEM settings
\
Mea-
suring
\
Cut-off Flow
.
If
Cut-off Flow
\
sign
and
user
are selected, 2 values have to be entered:
If
Cut-off Flow
\
absolut
and
user
are selected, only one value have to be entered:
Enter
0
(zero) to switch off the outliers check.
Enter a limit > 0 to switch on the outliers checking. The measured flow velocity will then be
compared to the entered upper limit.
Press ENTER.
Note!
If the upper limit is too low, a measurement might be impossible because most of the measured val-
ues will be marked as "invalid".
Select
sign
to define a cut-off flow depending on the flow direction. Two independent limits
are set for the positive and negative flow directions.
Select
absolut
to define a cut-off flow independent of the flow direction. A limit is set for
the absolute value of the flow velocity.
Press ENTER.
Select
factory
to use the default limit of 2.5 cm/s (0.025 m/s) for the cut-off flow.
Select
user
to enter the cut-off flow.
Press ENTER.
Enter the cut-off flow. Press ENTER.
All positive values of the flow velocity smaller than this limit are set to zero.
Enter the cut-off flow. Press ENTER.
All negative values of the flow velocity greater than this limit will be set to zero.
Enter the cut-off flow. Press ENTER.
The absolute value of all flow velocity values lower than this limit will be set to zero.
Velocity limit
0.0
m/s
Cut-off Flow
absolut
>SIGN<
Cut-off Flow
factory
>USER<
+Cut-off Flow
2.5
cm/s
-Cut-off Flow
-2.5
cm/s
Cut-off Flow
2.5
cm/s
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